Method of installing a quick change load wheel assembly

ABSTRACT

A load wheel assembly for a materials handling vehicle includes first and second spaced side members, at least one rotatable roller extending between the first and second side members. An interface structure provides a substantially rigid connection between the load wheel assembly and a mounting structure on the materials handling vehicle. The mounting structure includes a transverse bar and the interface structure includes a portion that engages and mates with the transverse bar to form a rigid connection between the interface structure and the transverse bar.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a DIVISIONAL APPLICATION of and claims priority toU.S. patent application Ser. No. 12/869,092, filed Aug. 26, 2010,entitled “OUTRIGGER ASSEMBLY WITH QUICK CHANGE LOAD WHEEL ASSEMBLY,”which is a continuation-in-part application of and claims priority toU.S. patent application Ser. No. 11/763,487, filed on Jun. 15, 2007, nowU.S. Pat. No. 7,845,657, granted Dec. 7, 2010, entitled “QUICK CHANGELOAD WHEEL ASSEMBLY,” the entire disclosures of which are incorporatedby reference herein.

FIELD OF THE INVENTION

The present invention relates generally to materials handling vehiclessuch as forklift trucks and, more particularly, to a quick change loadwheel assembly that may be quickly mounted on and removed from astraddle arm or an outrigger on a materials handling vehicle.

BACKGROUND OF THE INVENTION

Forklift trucks, such as rider reach and stock picker trucks, aretypically provided with a pair of forwardly extending straddle armsmounted outside of vertically movable forks of the trucks where they donot impede lowering of the forks to the floor, and do not interfere withany load supported upon the forks. The straddle arms each carry one ormore load wheels to support the weight of the truck and any load carriedby the forks. After use over a period of time, the load wheels normallyexperience wear or may become damaged and require replacement.

A known construction for a base leg assembly for a straddle armincluding load wheels for a lift truck is illustrated in U.S. DesignPatents No. D505,763 and D499,853 and also in U.S. Patent ApplicationPublication No. 2005/0034929 A1. The base leg assembly has a mountingplate, a base leg and a load wheel assembly. The base leg has anintegrally cast mounting portion and a leg portion that extendslaterally from the mounting portion and transitions in directionapproximately 90° such that the leg portion extends forward of themounting portion and the lift truck at its distal end. A load wheelassembly includes a pair of load wheel plates which are mirror images ofeach other and have inner surfaces that engage the outer surface of thedistal end of the leg portion of the base leg. The load wheel plates arefastened to the base leg using threaded fasteners. An elongated apertureextends transversely through each load wheel plate and receives loadwheels. The elongated apertures are shaped such that they can receivedifferent numbers, sizes, and types of load wheels which are disposedbetween the load wheel plates and supported such that they can rotate.

In order to remove the load wheel assembly from the straddle arm, thefasteners securing the load wheel plates to the leg portion of the baseleg are removed to release the wheel plates. For reassembly, load wheelsof a required size and type are disposed between the load wheel plateswhich are then moved into position so that the plates can be resecuredto the leg portion of the base leg by the fasteners that were previouslyremoved. Since this type of repair is typically performed in the field,it can be difficult and require care in manipulating the load wheels andload wheel plates for reinstallation.

In another configuration for mounting load wheels to a straddle arm, amounting structure comprising a weldment having spaced bearing plates islocated at the end of the straddle arm. Pivot plates located inapertures in each of the bearing plates support wheel axles for twospaced wheels. In order to replace the wheels, the axles must beremoved, resulting in release of the wheels as well as various washersand bearings supported on the wheels and axles. A repair operationperformed in the field can be difficult in that the procedure forassembling replacement wheels into the bearing plate requiresmanipulating various parts onto the axles as the axles are moved intoposition in the pivot plates. Such a repair operation can be furthercomplicated by the location of the of load wheel structure adjacent thefloor surface limiting access to the parts positioned between thebearing plates.

SUMMARY OF THE INVENTION

In accordance with an aspect of the invention, a method is provided forinstalling a load wheel assembly on an outrigger for a materialshandling vehicle. The outrigger may comprise an outrigger box comprisinga pair of laterally spaced bearing plates defining a load wheel openingfor receiving a load wheel assembly, and a transverse bar extendinglaterally across the load wheel opening. The load wheel assembly maycomprise at least one roller supported on an axle between a pair of sidesupport members and an interface structure extending between the pair ofside support members. The method comprises: positioning the load wheelassembly in the load wheel opening with the interface structure locatedabove the transverse bar, engaging at least one threaded fastenerbetween the interface structure and the transverse bar, and rotating thefastener to draw the transverse bar toward engagement with the interfacestructure.

In accordance with another aspect of the invention, a method is providedfor installing a load wheel assembly on an outrigger for a materialshandling vehicle. The outrigger may comprise an outrigger box comprisinga pair of laterally spaced bearing plates defining a load wheel openingfor receiving a load wheel assembly, and a transverse bar extendinglaterally across the load wheel opening. The load wheel assembly maycomprise at least one roller supported on an axle between a pair of sidesupport members and an interface structure extending between the pair ofside support members. The method comprises: providing an assemblyretention tool having side member engagement structure, locating theside support members adjacent to the side member engagement structure todefine a load wheel preassembly, positioning the preassembly over theload wheel opening, and lowering the load wheel assembly from theretention tool into the load wheel opening.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed that thepresent invention will be better understood from the followingdescription in conjunction with the accompanying Drawing Figures, inwhich like reference numerals identify like elements, and wherein:

FIG. 1 is a perspective view of a typical forklift truck incorporatingthe present invention;

FIG. 2 is a perspective view of the end of a straddle arm of theforklift truck of FIG. 1;

FIG. 3 is a view similar to FIG. 2 with a load wheel assemblydisassembled from the straddle arm;

FIGS. 3 a and 3 b are views similar to FIG. 3 but illustrating removablebearing plates and an alternate fastener and interface structure;

FIG. 4 is an exploded perspective view of the load wheel assembly;

FIG. 5 is an enlarged cross-sectional view taken along line 5-5 in FIG.6;

FIG. 6 is a side elevational view of an end portion of the straddle armillustrating a position for replacement of the load wheel assembly;

FIG. 7 is a perspective view of a load wheel assembly incorporating thepresent invention and having a single wheel inserted horizontally into aload bearing structure;

FIG. 8 is a perspective view of the end of a straddle arm of theforklift truck with a further embodiment of a load wheel assembly showndisassembled from the straddle arm;

FIG. 9 is an exploded view of the load wheel assembly of FIG. 8;

FIG. 10 is an exploded view of an alternative configuration of the loadwheel assembly of FIG. 9;

FIG. 11 is a cross-sectional view illustrating the load wheel assemblyof FIG. 10 located in a retention tool;

FIG. 12 is a cross-sectional view illustrating the load wheel assemblyof FIG. 10 in a transferred position from the retention tool to a loadwheel opening in an outrigger box;

FIG. 13 is a perspective view of the load wheel assembly of FIG. 10positioned in the load wheel opening of the outrigger box prior toengagement of an interface structure of the load wheel assembly with amounting structure of the straddle arm; and

FIG. 14 is a cross-sectional view of the load assembly of FIG. 10engaged with the mounting structure of the straddle arm.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description of the preferred embodiment,reference is made to the accompanying drawings that form a part hereof,and in which is shown by way of illustration, and not by way oflimitation, specific preferred embodiments in which the invention may bepracticed. It is to be understood that other embodiments may be utilizedand that changes may be made without departing from the spirit and scopeof the present invention.

Reference is now made to FIG. 1 which shows a materials handling vehicleincorporating the present invention. The vehicle comprises, in theillustrated embodiment, a rider reach forklift truck 10. The truck 10includes a frame 12, a drive mechanism 14 supported on the frame 12, amast assembly 16 coupled to the frame 12, an operator's compartment 18and an overhead guard 20. The drive mechanism 14 includes a power unit22 which houses a battery (not shown) for supplying power to a tractionmotor (not shown) connected to a steerable, powered wheel 24 and tohydraulic motors (not shown) which supply power to several differentsystems.

The truck is supported at four points which are provided by thesteerable, powered wheel 24 located at the left rear of the power unit22, a caster wheel 26 located at the right rear of the power unit 22,and two load wheel assemblies 28 supported on a pair of outriggerassemblies or straddle arms 30 (only one of which, the left straddlearm, is shown in FIG. 1) extending from the power unit 22 at the frontof the truck 10. The straddle arms 30 are attached to the power unit 22so that they extend outwardly beyond the sides of the mast assembly 16to allow a pair of forks 32 to be lowered to the floor between thestraddle arms 30 without interference, and so that the straddle arms 30do not interfere with any load supported on the forks. Referringadditionally to FIG. 2, each straddle arm 30 comprises a forwardlyextending solid steel bar or arm member 34. A load bearing structure 36comprising a pair of bearing plates 36 a, 36 b is located at the forwardend of the arm member 34 with the load wheel assembly 28 supportedbetween the pair of bearing plates 36 a, 36 b. The bearing plates 36 a,36 b are illustrated as being a solid extension of the arm member 34 forexample by having the bearing plates 36 a, 36 b and arm member 34comprise a weldment or by being cast as a single integral unit. However,it should be understood that the present invention is not limited to aparticular structure for providing the bearing plates 36 a, 36 b at theend of the arm member 34. The bearing plates 36 a, 36 b may comprise,for example, separate plate members that are attached to the end of thearm member 34, such as by bolting individual bearing plates 36 a, 36 bto the arm member 34. In any event, the assembly and disassemblyoperations described for the load wheel assemblies 28 do not requireremoval or reattachment of the bearing plates 36 a, 36 b from or to thearm member 34.

Referring to FIGS. 3 and 4, the illustrated load wheel assembly 28includes a first side member 42 a and a second side member 42 b locatedin laterally spaced relation to the first side member 42 a. The sidemembers 42 a, 42 b are elongated having a major longitudinal axis L anda minor height axis H. First and second rollers or wheels 44, 46 aresupported for rotation on respective first and second axles 48, 50 todefine a roller structure 43. The first and second axles 48, 50 extendtransversely between the side members 42 a, 42 b with the ends of theaxles 48, 50 being received within openings 49 a, 49 b in the respectiveside members 42 a, 42 b. Each of the wheels 44, 46 may comprise knownload wheels including a tire 52 supported on a hub portion 54 whichincludes a bearing 56 for engaging with a respective axle 48, 50. Itshould be noted that the roller structure 43 may comprise structureother than that specifically described herein, and the roller structure43 may comprise any load carrying assembly that provides a floorengaging component for reducing resistance between the straddle arm 30and the floor as the truck 10 is maneuvered across the floor. Further,while two wheels 44, 46 are shown in the illustrated embodiment, theroller structure can have a single wheel or more than two wheels asrequired for a given application.

The roller structure 43 is maintained in the side members 42 a, 42 b bya retainer illustrated as comprising a type of snap ring 58 known ascirclips snapped into annular slots at the ends of the axles 48, 50.Alternately, retention structure can comprise other fastening devicesassociated with the axles 48, 50 or the side members 42 a, 42 b as willbe apparent to those skilled in the art. The retention structure caneven simply be tape secured to cover the openings 49 a, 49 b in therespective side members 42 a, 42 b or wrapped around the rollerstructure 43 and the side members 42 a, 42 b prior to installation.Whatever retainer or retention structure is used, the assemblycomprising the roller structure 43 and the retained side members 42 a,42 b define an assembled roller unit 60 for the load wheel assembly 28.

The load wheel assembly 28 further includes an interface structure 62for providing a substantially rigid connection between the load bearingstructure 36 and the assembled roller unit 60. In the illustratedembodiment, the interface structure 62 comprises a block member 64rigidly attached to a pivot pin 66. The block member 64 may be attachedto the pivot pin 66 by any conventional method, for example by welding,or the block member 64 and pivot pin 66 may be formed as a unitarymember. The pivot pin 66 extends transversely to the longitudinal axis Land the height axis H, and is mounted for rotation to the framestructure 40 at pivot apertures 68 a, 68 b formed in the respective sidemembers 42 a, 42 b, generally centrally of the side members 42 a, 42 b,i.e., between the first and second wheels 44, 46 as illustrated. Theends of the pivot pin 66 are engaged with bearing members 68 locatedwithin the pivot apertures 68 a, 68 b. The pivot pin 66 forms a pivotstructure about which the assembled roller unit 60 may pivot.

Referring to FIGS. 2 and 3, the load bearing structure 36 includes amounting structure comprising a transverse bar 70 extending between andrigidly attached to the bearing plates 36 a, 36 b. The bearing plates 36a, 36 b and bar 70 can be connected to one another by welding oralternately could be formed as a single casting or part. The bar 70includes an aperture 72 through which a threaded fastener 74 of theinterface structure 62 may extend to engage a threaded aperture 76defined through an upper surface 82 of the block member 64. Thus, asillustrated in FIGS. 2-4, a single, downwardly inserted bolt secures thewheel assembly 28 to the load bearing structure 36. It is noted that abolt could be inserted upwardly with the aperture 72 being threaded toreceive the bolt and other fasteners can be used to secure the wheelassembly to the load bearing structure 36. For example, a stud S can beformed on either the wheel assembly 28 or the bar 70 to be received in areceiving aperture in the other structure with the stud S being securedby means of a roll pin RP or otherwise, see FIG. 3 a. FIG. 3 a alsoillustrates individual bearing plates 36 a, 36 b which can be bolted tothe arm member 34.

Referring to FIG. 5, the bar 70 includes a pair of holes 84, where eachhole 84 comprises a lower hole portion 84 a extending upwardly from alower surface 86 of the bar 70, and a smaller diameter upper holeportion 84 b extending upwardly from the lower hole portion 84 a to anupper surface 87 of the bar 70. The block member 64 includes a pair ofpins 80 extending upwardly from its upper surface 82 for engaging withinthe lower hole portions 84 a of the bar 70. Each of the bearing plates36 a, 36 b additionally includes a downwardly facing cutout area 85(only one shown in FIG. 3) for receiving correspondingly structuredupper surfaces of the side members 42 a, 42 b, and the bearing plates 36a, 36 b and bar 70 define a downwardly facing opening of the loadbearing structure 36. During an operation to mount the load wheelassembly 28 to the load bearing structure 36, the load wheel assembly 28and side members 42 a, 42 b are moved relative to one another toposition the side members 42 a, 42 b into the cutout areas 85. Inaddition, the upper surface 82 of the block member 64 moves intoengagement with the lower surface 86 of the bar 70, see FIG. 3.

The pins 80 slide into openings of the lower hole portions 84 a at thelower surface 86 of the bar 70 and include tapered ends to facilitatealignment of the block member 64 to the bar 70 so that the aperture 76in the block member 64 is aligned to the aperture 72 in the bar 70. Thefastener 74 may then be inserted through the aperture 72 and threadablyengaged in the aperture 76 to retain the block member 64 in engagementwith the bar 70. The pins 80 provide structure that, in combination withthe fastener 74, substantially prevent relative shearing movementbetween the block member 64 and the bar 70, and further resistside-to-side movement of the assembled wheel unit 60 relative to theload bearing assembly 36.

Other arrangements for substantially preventing relative shearingmovement between the block member 64 and the bar 70 will be apparent tothose skilled in the art. For example, a tenon T and mortis (not shown)joint is illustrated in FIG. 3 b. FIG. 3 b also illustrates individualbearing plates 36 a, 36 b which can be bolted to the arm member 34.

As noted above, alternative configurations for attaching the blockmember 64 to the bar 70 include, for example, inserting the fastener 74upwardly through the block member 64 and threadably engaged it with thebar 70 and a stud and roll pin. Other attachment arrangements will beapparent to those skilled in the art in view of this description.

Reference to FIG. 6 will now be made to describe an operation forreplacing a load wheel assembly 28. The end of the straddle arm 30 maybe initially lifted from the floor surface 88, such as by application ofa lifting force F to a portion of the straddle arm 30, to create anaccess space 90 between the floor surface 88 and the lower edge 92 ofthe load bearing structure 36. The fastener 74 may be removed to permitthe block member 64 to separate from the bar 70 and to permit the loadwheel assembly 28 to be lowered downwardly as an assembled unit from theload bearing structure 36. A punch and hammer can be used in holes 84 bto assist removal. A replacement load wheel assembly 28 may then beinserted by moving it into the access space 90 and positioning itupwardly into engagement with the load bearing structure 36, asdescribed above.

Alternately, the fastener 74 can be first removed and the straddle arm30 lifted so that the straddle arm is lifted off of the wheel assembly28. The replacement load wheel assembly 26 is then positioned in theaccess space 90 and the end of the straddle arm 30 may be lowered tobring the bar 70 of the load bearing structure 36 into engagement withthe block member 64 of the load wheel assembly 28.

In either event, at least one fastener extending between the straddlearm or outrigger and load wheel assembly is disengaged and an originalwheel assembly is moved out of engagement with the outrigger. Areplacement wheel assembly is moved into engagement with the outriggerand the at least one fastener is engaged between the replacement wheelassembly and the outrigger to maintain the wheel assembly in engagementwith the outrigger.

While the illustrated embodiments to this time have relied on verticalmovement between a wheel assembly and the load bearing structure, itshould be apparent that horizontal movement may also be used to removeand replace a load wheel assembly. Such horizontal movement wouldrequire less elevation of the load bearing structure and the movementbetween the load wheel assembly and the load bearing structure could besideways or from the front of the load bearing structure. For example, aload wheel assembly 28′ having a single wheel 44′ is shown in FIG. 7 asbeing inserted into the load bearing structure 36′ with the load wheelassembly 28′ having a tenon T that mates with a mortis M on the loadbearing structure 36′. The components in FIG. 7 that correspond tosimilar elements in the previously described embodiments are labeledwith the same reference numerals primed.

It can be seen from the above description that the structure for theload wheel assembly 28 provides an efficient load wheel replacementoperation in that an uncomplicated interface structure 62 is providedcomprising, for example, the single fastener 74 engaged with the blockmember 64 for attachment and removal of the load wheel assembly 28,requiring minimal manipulation of parts during a replacement or repairoperation. Further, the pins 80 or tenon T of the interface structure 62readily engage with the holes 84 or mortis M of the bar 70 to facilitatepositioning of the load wheel assembly 28 relative to the load bearingstructure 36, while also strengthening the connection between the twocomponents.

Referring to FIGS. 8 and 9, an alternative embodiment for an outriggerassembly including a quick change load wheel assembly is illustratedthat may be incorporated into an outrigger or straddle arm 30 of amaterials handling vehicle, such as a forklift truck 10, as illustratedin FIG. 1. Elements of the outrigger assembly of FIGS. 8 and 9corresponding to elements of the previously described embodiments arelabeled with the same reference numeral increased by 100.

As seen in FIG. 8, a load bearing structure 136 of the presentembodiment defines an outrigger box 135 including a pair of bearingplates 136 a, 136 b laterally spaced from each other and extending in alongitudinal direction of the straddle arm 30 (FIG. 1). The bearingplates 136 a, 136 b define a load wheel opening 137 therebetween. Atransverse bar 170 extends through a longitudinal mid-portion of theload wheel opening 137 and includes opposing ends rigidly attached tothe bearing plates 136 a, 136 b. The transverse bar 170 may be welded tothe bearing plates 136 a, 136 b to form the outrigger box 135 as a rigidweldment. In addition, an outrigger tip 139 may be attached to the loadbearing structure 136, such as by bolts (not shown) attaching theoutrigger tip 139 to the bearing plates 136 a, 136 b, to enclose anouter end of the load wheel opening 137.

Referring further to FIG. 9, the outrigger assembly includes a loadwheel assembly 128 including side support members comprising a firstside member 142 a and a second side member 142 b located in laterallyspaced relation to the first side member 142 a. First and second rollersor wheels 144, 146 are supported for rotation on respective first andsecond axles 148, 150. The first and second axles 148, 150 extendtransversely between the side members 142 a, 142 b with the ends of theaxles 148, 150 being received within openings 149 a, 149 b in therespective side members 142 a, 142 b. The wheels 144, 146 may compriseknown load wheels including a tire 152 supported on a hub portion 154which includes a bearing 156 for engaging with a respective axle 148,150. In addition, a bearing shield or spacer 161 may be providedadjacent an outer end of each of the bearings 156 to space the bearings156 from a respective side member 142 a, 142 b.

The axles 148, 150 are maintained in engagement in the openings 149 a,149 b by a retainer, such as a snap ring 158, i.e., a circlip, engagedin an annular slot or groove in each end of the axles 148, 150. Theopenings 149 a, 149 b are preferably formed with a D-shapedcross-section for receiving similarly shape ends of the axles 148, 150.A recess 159 is provided in an outer end of each of the openings 149 a,149 b for receiving the snap ring 158 substantially flush within theside of the respective side members 142 a, 142 b.

The load wheel assembly 128 further includes an interface structure 162for providing a substantially rigid connection between the load bearingstructure 136 and the load wheel assembly 128. In the illustratedembodiment, the interface structure 162 comprises a block member 164,and includes pivot pin ends 166 extending from opposing lateral sides ofthe block member 164. The pivot pin ends 166 may be integrally formedwith the block member 164. For example, the block member 164 may be amachined part with the pin ends 166 formed at the opposing ends thereof.Alternatively, the pivot pin ends 166 may comprise the ends of a pivotpin (not shown) extending through or attached to the block member 164.The pivot pin ends 166 engage in pivot apertures 168 a, 168 b formed inthe respective side members 142 a, 142 b, generally centrally of theside members 142 a, 142 b, i.e., between the first and second wheels144, 146, as illustrated in FIGS. 8 and 9. Further, the pivot pin ends166 are engaged with bearing members 168 located within the pivotapertures 168 a, 168 b. The pivot pin ends 166 engaged in the bearingmembers 168 form a pivot structure about which the load wheel assembly128 may pivot relative to the load bearing structure 136.

The block member 164 of the interface structure 162 is adapted to engagethe transverse bar 170 of the load bearing structure 136. In particular,a lower surface 181 (FIG. 9) of the block member 164 may be located inengagement with an upper surface 187 (FIG. 8) of the transverse bar 170.The block member 164 includes a pair of laterally spaced throughapertures 176 for receiving a pair of shoulder bolts 174 therethrough,and the transverse bar 170 includes a pair of threaded apertures 172(only one shown in FIG. 8) for receiving a threaded end of the bolts174, as will be described further below. The shoulder bolts 174 arepreferably of sufficient strength to transfer load forces from the loadbearing structure 136, at the end of the straddle arm 30, to the loadwheel assembly 128. For example, the shoulder bolts 174 may comprise asteel metric bolt M12×1.75 having a thread length of about 18 mm and ashoulder length of about 50 mm. Further, the bolts 174 preferably have aproperty class designation of 12.9, i.e. a minimum tensile strength ofabout 1100 MPa, and a minimum shear strength of about 660 MPa.

Referring to FIG. 10, the outrigger assembly may comprise a load wheelassembly 128′ having an alternative configuration for the axles 148′,150′ and the side members 142 a′, 142 b′ for enabling the load wheelassembly 128′ to support a greater load. In particular, the side members142 a′, 142 b′ may be formed with openings 149 a′, 149 b′, respectively,that do not include the recesses 159 illustrated in FIG. 9. That is, theopenings 149 a′, 149 b′ may be formed as a continuous surface extendingbetween the opposing planar sides of the side members 142 a′, 142 b′.Hence, the openings 149 a′, 149 b′ through the side members 142 a′, 142b′ present a greater surface area for engagement with the ends of theaxles 148′, 150′. Further, the ends of the axles 148′, 150′ may beformed without a groove or other structure to receive the snap ring 158,and may define a continuous surface for engagement with respectivesurfaces of the openings 149 a′, 149 b′. The additional load bearingarea defined by the contact between the ends of the axles 148′, 150′ andthe surfaces of the holes 149 a′, 149 b′ is believed to provideadditional load carrying capacity to the side members 142 a′, 142 b′ inthe area of the ends of the axles 148′, 150′. As in the configurationdescribed with reference to FIGS. 8 and 9, the openings 149 a′, 149 b′are preferably formed with a D-shaped cross-section for receivingsimilarly shaped ends of the axles 148′, 150′.

It may be noted that, since the load wheel assembly 128′ described withreference to FIG. 10 does not include a retention structure, such as thesnap ring 158, to retain the side members 142 a′, 142 b′ in engagementwith the ends of the axles 148′, 150′ and with the pin ends 166 of theinterface structure 162′, a retention tool 194 may be provided to retainthe load wheel assembly 128′ in an assembled state, i.e., with sidemembers 142 a′, 142 b′ in engagement with the axles 148′, 150′ and withthe interface structure 162′, when it is not positioned in the loadwheel opening 137 (FIG. 8). The retention tool 194 may comprise aC-shaped frame 196 including opposing side member engagement structurecomprising side plates 196 a, 196 b and a base plate 196 c extendingbetween and oriented perpendicular to the side plates 196 a, 196 b. Theside plates 196 a, 196 b may be formed integrally with the base plate196 c, such as by being formed from a single plate or cast as a unitarymember, or may comprise a weldment. Further, it should be understoodthat the retention tool 194 may comprise other configurations than theparticular C-shaped structure described herein, to the extent that analternative configuration may perform the function of the retention tool194 for installing and/or removing the load wheel assembly 128′ to andfrom the outrigger box 137, as described below.

Referring further to FIG. 11, the retention tool 194 includes a threadedscrew member 198 having a threaded shank 198 a and a handle 198 b. Afirst threaded nut 200 is threadably engaged on the shank 198 a and islocated between the handle 198 b and an upper surface 202 of the baseplate 196 c. A second threaded nut 204 is threadably engaged on theshank 198 a on a side of the base plate 196 c opposite from the firstnut 200. The retention tool 144 may be engaged with the load wheelassembly 128′ by at least partially threading the threaded shank 198 ainto a threaded aperture 206 in the block member 164′. The first nut 200may be rotated on the threaded shank 198 a to move the first nut 200toward the block member 164′ to a location on the threaded shank 198 awhere the assembled load wheel assembly 128′ is positioned with at leastan upper portion of the side members 142 a′, 142 b′ located inengagement with respective inner surfaces 197 a, 197 b of the sideplates 196 a, 196 b, as seen in FIG. 11. The lower nut 204 may belocated at a predetermined fixed position to define a stop position forupward movement of the screw member 198 through the base plate 198 c.Further, the second nut 204 may prevent the screw member 198 frombecoming separated from the base plate 196 c when not engaged with theload wheel assembly 128′.

The load wheel assembly 128′ retained within the retention tool 194comprises a load wheel preassembly 207 (FIG. 11) for installation in theoutrigger box 135. As seen in FIG. 11, the load wheel preassembly 207 islocated with the side plates 196 a, 196 b engaged on upper portions ofthe bearing plates 136 a, 136 b. The side plates 196 a, 196 b includerespective recessed areas 208 a, 208 b for receiving the upper portionsof the bearing plates 136 a, 136 b, with a tab portion 209 a, 209 b ofthe side plates 196 a, 196 b extending along an outer portion of thebearing plates 136 a, 136 b, to align the retention tool 194 in alateral direction relative to the outrigger box 135. Further, the innersurfaces 197 a, 197 b of the retention tool side plates 196 a, 196 b aresubstantially aligned with inner surfaces of the bearing plates 136 a,136 b in cutout or recess areas 185 defined in the bearing plates 136 a,136 b for receiving a respective one of the side members 142 a′, 142 b′and for accommodating pivoting movement of the side members 142 a′, 142b′.

As seen in FIG. 12, the load wheel assembly 128′ may be lowered from theretention tool 194 into the load wheel opening 137 by rotating the firstnut 200 to permit the load wheel assembly 128′ to move downwardly awayfrom the base plate 196 c, to engage the wheels 144, 146 in contact witha support surface, such as a floor surface, wherein the wheels 144, 146may be located on either side of the transverse bar 170. The screwmember 198 may then be rotated to disengage the threaded shank 198 afrom the threaded aperture 206 in the block member 164, and theretention tool 194 may be removed from the outrigger box 135. Subsequentto lowering the load wheel assembly 128′ into the load wheel opening137, the lower surface 181 of the block member 164′ is located in spacedrelation above the upper surface 187 of the transverse bar 170. Further,the bearing plates 136 a, 136 b may rest on the support surface prior toengagement of the block member 164′ with the transverse bar 170.

During an assembly operation for engaging the block member 164′ with thetransverse bar 170, the bolts 174 may be inserted through the blockmember apertures 176 and into threaded engagement in the transverse barapertures 172, see FIG. 13. Further, the bolts 174 may be rotated todraw the transverse bar 170 toward the block member 164′, therebylifting the load bearing structure 136 from the support surface. Forexample, the bolts 174 may be alternately rotated to alternately movethe transverse bar 170 a portion of the distance upwardly toward theblock member 164′ until the upper surface 187 of the transverse bar 170engages and mates with the lower surface 181 of the block member 164′,forming a substantially rigid connection between the interface structure162′ and the transverse bar 170, as seen in FIG. 14.

It should be understood that the load wheel assembly 128 described withreference to FIGS. 8 and 9 may be installed on the load bearingstructure 136 by a substantially similar operation, with the exceptionthat the load wheel assembly may be positioned in the load wheel openingwithout the use of the retention tool 194. Hence, the load wheelassemblies 128, 128′ may be installed on the load bearing structure 136without the use of a jack or other implement to support the ends of thebearing plates 136 a, 136 b in spaced relation to the support surface asthe load wheel assembly 128, 128′ is located in its installed positionrelative to the load bearing structure 136.

Further, the load wheel assembly 128, 128′ may be removed by looseningthe bolts 174, resulting in the bearing plates 136 a, 136 b loweringinto resting engagement on the support surface. In the case of the loadwheel assembly 128′, the retention tool 194 may be positioned over theload wheel assembly 128′ after removal of the bolts 174. The screwmember 198 may be engaged with the threaded hole 206 in the block member164 (FIG. 12), and the first nut 200 may be rotated to move the loadwheel assembly 128′ upwardly to the position illustrated in FIG. 11 forremoval of the load wheel assembly 128′ from the load wheel opening 137.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. A method of installing a load wheel assembly onan outrigger for a materials handling vehicle, the outrigger comprisingan outrigger box comprising a pair of laterally spaced bearing platesdefining a load wheel opening for receiving a load wheel assembly, and atransverse bar extending laterally across said load wheel opening, andsaid load wheel assembly comprising at least one roller supported on anaxle between a pair of side support members and an interface structureextending between said pair of side support members, the methodcomprising: positioning said load wheel assembly in said load wheelopening with said interface structure located above said transverse bar;engaging at least one threaded fastener between said interface structureand said transverse bar; and rotating said fastener to draw saidtransverse bar toward engagement with said interface structure.
 2. Themethod of claim 1, wherein said rotating said fastener effects avertical movement of said outrigger from a support surface wherein saidat least one roller supports said outrigger in spaced relation to saidsupport surface during said vertical movement of said outrigger.
 3. Themethod of claim 2, wherein two fasteners are located in laterally spacedrelation to each other and engaged between said interface structure andsaid transverse bar, and said rotating said fastener comprisesalternately rotating each of said fasteners to move said transverse bara portion of the distance toward said interface structure.
 4. The methodof claim 1, including providing an assembly retention tool having sidemember engagement structure and, prior to positioning said load wheelassembly in said load wheel opening, locating said side memberengagement structure of said assembly retention tool adjacent at least aportion of said side support members to retain said side support membersin engagement with said axle and said interface structure to define aload wheel preassembly.
 5. The method of claim 4, including positioninga lower portion of said load wheel preassembly in said load wheelopening and displacing said side support members downwardly into saidload wheel opening and away from said side plates of said assemblyretention tool.
 6. The method of claim 5, wherein said positioning saidlower portion of said load wheel preassembly in said load wheel openingincludes lowering said load wheel preassembly into recessed areas formedin said bearing plates.
 7. The method of claim 4, wherein said sidesupport members each comprise an aperture for receiving a respective endof said axle, each said aperture receiving said respective ends of saidaxle in sliding engagement, and said side support members beingpositioned in engagement with an inner surface of one of said bearingplates for retaining said side support members in engagement with saidends of said axle.
 8. The outrigger assembly of claim 7, wherein saidinner surfaces of said bearing plates comprise recessed areas forreceiving said side support members therein.
 9. The method of claim 4,wherein said side member engagement structure comprises a pair oflaterally spaced side plates supported on a base plate.
 10. The methodof claim 9, wherein said interface structure includes a threadedaperture and said assembly retention tool includes a threaded shank anda nut located adjacent to said base plate and engaged on said threadedshank, said locating said side member engagement structure adjacent saidside support members to define a load wheel preassembly comprising:threading said threaded shank into said threaded aperture of saidinterface structure; and rotating said nut on said threaded shank todraw said interface structure toward said base plate.
 11. The method ofclaim 10, wherein, prior to said positioning said load wheel assembly insaid load wheel opening, removing an initial load wheel assembly fromsaid load wheel opening including rotating a fastener located inengagement with said initial load wheel assembly to effect loweringmovement of said outrigger to engagement with said support surface. 12.The method of claim 11, further including: placing said assemblyretention tool over said initial load wheel assembly; threading saidthreaded shank into said threaded aperture of said interface structureof said initial load wheel assembly; and rotating said nut on saidthreaded shank to draw said interface structure from said load wheelopening.
 13. A method of installing a load wheel assembly on anoutrigger for a materials handling vehicle, the outrigger comprising anoutrigger box comprising a pair of laterally spaced bearing platesdefining a load wheel opening for receiving a load wheel assembly, and atransverse bar extending laterally across said load wheel opening, andsaid load wheel assembly comprising at least one roller supported on anaxle between a pair of side support members and an interface structureextending between said pair of side support members, the methodcomprising: providing an assembly retention tool having side memberengagement structure; locating said side support members adjacent tosaid side member engagement structure to define a load wheelpreassembly; positioning said preassembly over said load wheel opening;and lowering said load wheel assembly from said retention tool into saidload wheel opening.
 14. The method of claim 13, wherein said positioningsaid load wheel assembly in said load wheel opening includes positioningsaid interface structure above said transverse bar, and furtherincluding: engaging at least one threaded fastener between saidinterface structure and said transverse bar; and rotating said fastenerto draw said transverse bar toward engagement with said interfacestructure.
 15. The method of claim 13, wherein said side memberengagement structure comprises a pair of laterally spaced side platessupported on a base plate, and said load wheel preassembly includes saidside support members located in engagement with inner surfaces of saidlaterally spaced side plates.
 16. The method of claim 15, wherein saidlaterally spaced side plates include respective recessed areas forreceiving upper portions of said side support members, said positioningsaid preassembly over said load wheel opening includes locating saidassembly retention tool on said outrigger box with upper portions ofsaid side support members received within said recessed areas.
 17. Themethod of claim 15, wherein said interface structure includes a threadedaperture and said assembly retention tool includes a threaded shank anda nut located adjacent to said base plate and engaged on said threadedshank, said locating said side member engagement structure adjacent saidside support members to define a load wheel preassembly comprising:threading said threaded shank into said threaded aperture of saidinterface structure; and rotating said nut on said threaded shank todraw said interface structure toward said base plate.